uma kirkwood

While PC is fun, lightweight, fire-retardant (it dissolves rather than inflames), it is also very absorbant, loves to drink up the moisture. Unless the permies/builders have come up with an affordable, 100% guaranteed against absorbancy mixture, I would not use it for your support walls, especially not underground.
But, it does make for a nice insulating plaster to finish out your home.

I hope someone with deeper research with newest technology (resins, etc) will correct me and give you the green flag. I'd be interested in learning about the 100% guaranteed advances made too.

Kelly Hart has a q/a on his site that might help answer some of your questions. From my research over the years, I would say "yep" to all to your questions, but I'm not the one to ask Here's Kelly's cool pantry page: http://www.greenhomebuilding.com/QandA/storefood/pantry.htm

Would so love to hear/see updates on your Spiral!

Jeff! How is your dbl-eco at Joshua tree performing for you? Is there anything you would like to do differently next time?

Oregon also has desert regions as well as it's rainforests and coasts. I believe Jackson Oregon is in the desert region, where many of the cob builders are experimenting.

Here is a blog by a man who built a cob back east in snow and humid regions. The lessons he learned are invaluable. http://www.small-scale.net/yearofmud/
The Year of Mud blog

Take a look at the Canadian Dirtbag blog. http://canadiandirtbags.wordpress.com/2012/11/

Your flower plan isn't that far off from the eCo Dome's at Cal Earth. It should be fun to do!

Here's a cool cold pantry that Owen did with a living roof: http://www.instructables.com/id/How-to-Build-an-Earthbag-Dome/

I appreciate the rusty wire comments and alerts, and I hope you'll forgive me for tossing in an opposing comment. Doesn't the barbed wire have to be in contact with the air in order to form rust? We see rusted barbed wire everywhere, yet it's still strong. When we pull a strand out of the ground that's been weather buried for years, it's as good as new and twice as strong. Perhaps there are different grades of metal used over the years or from brand to brand? I think I'll build a test dome, a dog house igloo, and tear it apart in 20 years and check out the wire. Between the heavy layers of adobe and the plaster as well, I doubt much air will be able to seep in and rust it too badly. Will see. Has anyone else tested theirs this/similar way?

How are the projects coming along? We've been saving winery bags, hope to build the shed this year so we can start the house next year. Looking forward to seeing the updates to all the projects here. (or links to them)

The electric netting should help quit a bit. Try placing peanut butter in strategic places (freshen it as needed), to teach the predators a new respect for electric fencing. All animals seem to love peanut butter.